Optical grating detecting instrument

Abstract

The invention discloses a grating detection instrument which is installed behind a collimating monochromatic outgoing beam sent out by a spectrograph. The grating detection instrument comprises a grating, a grating rotating stage and a light energy detector; the grating is rotationally mounted on the grating rotating stage which is positioned between the spectrograph and the light energy detector; and a lens is arranged between the light energy detector and the grating, and satisfies the formula: Gamma is equal to or larger than d multiplied by d1 / Lambada multiplied by t, wherein, Gamma refers to the angular magnification of the lens, d refers to the grating constant of the grating, Lambada refers to the wavelength of the collimating monochromatic outgoing beam emitted by the spectrograph, t refers to the distance from the lens to the inlet of the light energy detector, and d1 refers to the diameter of the inlet of the light energy detector. The grating detection instrument equipped with the lens provided by the invention can prevent diffraction beams from mutual interposition. The inlet of the light energy detector allows only one diffraction beam to pass through. In addition, the invention is suitable for use with a common spectrograph, and has the advantages of universal applicability and high detection precision.

Description

technical field [0001] The invention mainly relates to detection equipment for optical elements in optical storage devices, and in particular to a grating detector for detecting gratings. Background technique [0002] With the continuous advancement of optical storage technology, the existing optical read-write head has developed into a multi-functional optical storage disc pickup that integrates blue light (405nm wavelength), red light (660nm) and infrared light (780nm). With the diversification of the functions of the optical read-write head, the complexity of the structure of the optical read-write head and the strictness of the performance requirements of each component have also increased rapidly. The working band of the optical read-write head can extend from the violet-blue 400nm band to the near-infrared 800nm ​​band, and the parameters such as the transmittance, reflectivity of the lens and the splitting ratio of the grating in the optical read-write head must meet ...

AI Technical Summary

Problems solved by technology

[0010] Among the above two methods, one needs to change the beam diameter of the spectrometer, and the other needs the spectrometer to have enough working space, which requires a spectrometer with corresponding characteristics to meet the requirements, which is not universally applicable; There is a common point that the light aperture of the light energy detector needs to be reduced, and the distance between the light beam and the light beam is very close, which is easy to affect the accuracy of detection due to alignment errors

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